Kinetics and Selectivity in Thermal Hydrocracking and Catalytic Hydrocracking of Asphaltenes

• 出 处: China Petroleum Processing & Petrochemical Technology
• 发表日期: 2011年01期
• 关键词: constants producing kinetics insoluble apparent processed cracking selectivity a

A pentane-insoluble mixture of asphaltenes was processed by thermal hydrocracking and catalytic hydrocracking over Ni-Mo/γ-Al2O3 catalyst in a microbatch reactor at 430 ℃.The experimental data of asphaltene conversion adequately fit second-order kinetics to give the apparent rate constants of 2.435×10-2 and 9.360×10-2 (wt frac)-1 min-1 for the two processes,respectively.A three-lump kinetic model is proposed to evaluate the rate constants for parallel reactions of asphaltenes producing liquid oil (k1) and gas+coke (k3),and consecutive reaction producing gas+coke (k2) from this liquid oil.The evaluated constants for asphaltenes hydrocracking,in the presence and absence of the catalyst,respectively,show that k1 is 2.430×10-2 and 9.355×10-2 (wt frac)-1 min-1,k2 is 2.426×10-2 and 6.347×10-3 min-1,and k3 is 5.416×10-5 and 4.803×10-5 (wt frac)-1 min-1.As compared with the thermal hydrocracking of asphaltenes,the catalytic hydrocracking of asphaltenes promotes liquid production and inhibits coke formation effectively.

A pentane-insoluble mixture of asphaltenes was processed by thermal hydrocracking and catalytic hydrocracking over Ni-Mo / γ-Al 2 O 3 catalyst in a microbatch reactor at 430 ° C. The experimental data of asphaltene conversion adequately fit second-order kinetics to give the apparent rate constants of 2.435 × 10-2 and 9.360 × 10-2 (wt frac) -1 min-1 for the two processes, respectively. A three-lump kinetic model is proposed to evaluate the rate constants for parallel reactions of asphaltenes producing liquid oil ( k1), and consecutive reaction producing gas + coke (k2) from this liquid oil. The evaluated constants for asphaltenes hydrocracking, in the presence and absence of the catalyst, respectively, show that k1 is 2.430 × 10 -2 and 9.355 × 10-2 (wt frac) -1 min-1, k2 is 2.426 × 10-2 and 6.347 × 10-3 min-1, and k3 is 5.416 × 10-5 and 4.803 × 10-5 ( wt frac) -1 min -1.As compared with the thermal hydrocracking of asphaltenes, the catalytic hydrocracking of asphaltenes promotes liquid production and inhibits coke layer effectively.